Research And Realization Of Automatic Positioning Technology For Second Drilling Of Anchor Plate By CNC

The anchor plate is a key component of the bridge steel cable fixing,and its processing quality is directly related to the safety of the bridge.The anchor plate processing technology is rough drilling,heat treatment and fine drilling.Therefore,the anchor hole needs secondary processing to ensure that the hole size and surface roughness meet the design requirements.At present in domestic,the anchor hole is mainly processed by radial drilling machine which is artificial,labor-intensive and inefficient.In order to improve the efficiency and accuracy,and realize automation of the anchor hole processing,a secondary machining of the anchor hole using a CNC machine tool was proposed.In this paper,the automatic positioning technology for the secondary drilling of the anchor plate using a CNC machine tool is studied based on visual inspection technology.In this paper,an automatic anchor positioning method is proposed based on the visual inspection technology.First,the large field camera of small focal length lens is used to coarsely position the anchor plate.Then,the small field view camera of large focal length lens is used to precisely position the single hole of the anchor plate one by one.Finally,the reference hole is used as a measurement reference and is obtained through coordinate transformation.After coordinate transformation,the precise coordinate of the XY plane of the anchor hole in the machine coordinate system is obtained.Besides,using the height sensor to measure the height of the anchor plate to compensate the Z coordinate.Achieve automatic positioning of the anchor plate.A kind of automatic secondary positioning and measurement system for anchor plate NC drilling was designed and developed,including mechanical part and measurement and control part.The mechanical part mainly includes a visual inspection device and an altitude measurement device.When the visual inspection device completes the fixation and adjustment of the camera and light source.And the height measurement device completes the related actions of the anchor plate height measurement.The measurement and control part includes hardware design and software design.The main hardware of the measurement and control system includes a coarse positioning camera,a fine positioning camera,a height sensor,a numerical control system,and an industrial control computer.The software design includes a measurement and control system software based on an industrial control computer and a visual inspection program based on a vision system.When the measurement and control system achieve the software implements communication between the industrial control computer and the numerical control system,height sensor,and visual inspection system.Also achieving functions such as data acquisition,data processing,and command transmission.The visual inspection program mainly achieve functions such as image acquisition,image processing,and result output.This article has carried on the experiments to test and verify the positioning accuracy of the automatic positioning system.The result shows that the deviation is less than or equal to 0.08 mm which meets the design requirements.And the machining efficiency is improved,which meets the requirements of on-site processing.